Hertzian-wave meter.



G. D. BABCOGK.

HERTZIAN WAVE METER.

APPLICATION rum) MAY 27, 1908.

918,256. v Patented Apr. 13, 1909.

8 van for fltfowm 1 nu- NORRIS PETERS cm, WASHINGTOII. D. c.

UNITED STATES PAEFEN T OFFICE.

CLIFFORD D. BABCOGK, OF NEW YORK, N. Y., ASSIGNOR TO THE UNITED WIRELESSTELEGRAPH COMPANY, A CORPORATION OF MAINE.

HERTZIAN-WAVE IIIE TER.

Application filed. May 27, 1908.

To all whom it may concern:

Be it known that I, CLIFFORD D. Bassoon, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Hertzianave Meters;and I do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

My invention relates to improvements in Hertzian wave meters, and theobject of my invention is to produce such a meter that will be efficientin action, and comparatively cheap to manufacture.

Another object of my invention is to pro duce such a meter that willhave a greater compactness combined with a more rigid and durableconstruction than those heretofore produced as well as the possibilityof a closer reading.

It is well known in I'IertZian-wave wire! less telegraphy, that thedistance to which it is possible to propagate signals depends amongother things upon the wave length used, and that therefore, it is verydesirable to know the lengths of the waves emitted when operating awireless station. In measuring these waves, however, the sendingapparatus should not be disturbed; and it is customary to employ aclosed oscillation circuit provided with a suitable capacity andinductance each of which may be ad justed at will. It is also well knownthat the frequency in an oscillating circuit varies inversely as thesquare root of the product of the capacity and inductance; andtherefore, we may, by suitably adjusting these quantities, cause theinstrument itself to indicate the length of the particular waves thatmay be impinging thereon at the moment.

with the above objects in view, my invention consists in a condenser,composed of a pair of concentric metal cylinders, suitably insulatedfrom, and adjustable longitudinally with relation to each other,provided with an inductance and suitable wave measuring devices, all asmore fully hereinafter disclosed and particularly pointed put in theclaims.

Referring to the accompanying drawings forming a part of thisspecification, in which like numerals refer to like parts in all theSpecification of Letters Patent.

Patented April 13, 1909.

Serial No. 435,289.

views :F igure 1, is a longitudinal sectional view through the cylindersand inductance of my wave meter. Fig. 2, an end elevational view of thesame, and Fig. 3, a diagram of the electric circuit employed.

1, represents an inner metallic cylinder, preferably of brass; 2, acylinder of insu lating material, preferably of ebonite, surrounding andattached to said brass cylinder 1'; 3, an air space; -I, an outermetallic preferably brass cylinder concentric with cylinder 1; 5, aninsulating preferably ebonite cylinder, surrounding and attached tocylinder i; and 6, an inductance preferably a copper wire coiled aroundthe ebonite cylinder 5, as shown.

7, is a suitable insulating handle, preferably of ebonite, for slidingcylinder 1 in and out of cylinder 4:; and S is a metallic arm rigid withcylinder 1, and provided with the graduated extension 9, bentat rightangles to said arm, and extending outside of and parallel to the axes ofsaid coil and cylinders, as shown. The extension 9, is provided with thescale 10, and the resilient metallic contact 11, which makes connectionwith successive coils of the inductance (3. beginning at the endopposite the handle T, while the cylinder 1, and consequently theextension 9, slides longitudinally. In other words, the construction sofar described constitutes a condenser, the capacity of which may bevaried at will by simply moving the cylinder 1, in and out of cylinderst. And this condenser is surroumled by the inductance G, joined withthe cylinder 1, and capable of being varied in value as the saidcylinder is moved in and out. The spirals of inductance 6, should bewound with open turns, as shown, or else they should be well insulatedfrom each other with ebonite or some other good insulator which does notvary with the frequency. A distance of from one eighth to one fourth ofan inch between spirals will give good results.

12, represents a metallic conductor such an arm of copper tubing, whichpasses inside cylinder 1; and which through its resilient metalcontactor 13, makes a sliding contact with said cylinder, as shown. Saidarm 12, is bent up over the coil 6, and. is at its other extremityjoined to said coil 6, at that end of said coil which is near the handle7. That is to say, the contactor 11 and extension 9, adjustably joinssaid cylinder 1 with one end of coil 6, and contactor 13 and arm 12,joins said cylinder with the other end of said coil; but the firstmentioned connection is adapted to cut in and cut out convolutions ofsaid coil as the cylinder 1 is adjusted, while the second alwaysconnects said cylinder and the first turn of said coil 6, no matter howmuch the cylin ders 1 and 4: may be displaced relatively to each other.

15, is a resilient contactor adapted to slide relatively to extension 9,and 16 is a wire connecting said contactor with the indicatinginstrument l7, and the cylinder 1. The instrument 17, may be a hot wiregalvanometer, a thermo-couple, or it may be a vacuum tube, or any othersuitable indicating device.

The circuit is diagrammatically shown in Fig. 8, from which it will beseen that there is in series with one of the condenser plates formed bythe insulated cylinder. 1, the variable inductance 6, and that theindicating instrument 17 is in a shunt across the condenser cylinders,the circuit of this shunt being completed through the condenser fromcylinder to cylinder 1.

The operation of my wave meter is as follows ':The capacities of thecylinder condenser is first measured for the various positions of thetwo cylinders; and the inductances of the spirals of the coil 6,included in the circuit, are likewise measured for the positions of thecontactor 11, corresponding to the various capacities determined. If Cdenotes the capacity of the cylinders for any position, and L the inductance of that part of the spiral included in the circuit for theposition in question,

' then the quantities L (J, or oscillation constants, which determinethe wave lengths, can be readily determined for various positions. As iswell known, if the oscillation constant is known for any particularcircuit, then the frequency of the oscillation for that circuit isobtained by dividing the number five millions by its oscillationconstant. Also, it is known that the velocity with which Hertzian wavestravel, when emitted from an aerial, is about one thousand million feetper second, and that the relation between their wave lengths and theirfrequency is expressed by the fact that the wave length in feetmultiplied by their frequency is approximately equal to the number onethousand millions. Again, the frequency in any circuit depends upon theoscillation constant, as above, and it is well known that the wavelength in feet equals two hundred multiplied by the oscillationconstant. So that either of the above relations will readily enable thewave length to be determined. For instance, suppose a sending aerial isemitting wireless telegraph Waves, the cylinder 1 will be adjusted bymeans of the handle 7 until the vacuum tube glows brightest or the otherindicator 17 shows its proper reading. \Vhen such is found to be thefact, the oscillation constant of the instrument agrees with that of theaerial, and the numerical value of the wave length, or frequency can beread upon the scales, according to whether it is graduated for wavelengths, or wave frequencies, and provided of course the oscillationconstant. lies within the range of the instrument.

Of course, I do not limit myself to the exact details of constructiondisclosed, since it is evident that the same may be varied withoutdeparting from the spirit of my invention.

That I claim is 1. In a I-Iertzian wave meter the combination of a pairof insulated metallic cylinders constituting a condenser; an inductancecoil surrounding said cylinders; a sliding connection between said coiland one of said cylinders; a sliding connection between said lattercylinder and said coil; and a wave indicator connected to both of saidcylinders, substantially as described.

In a Hertzian wave meter the combination of a pair of insulated metalliccylinders adapted to slide one within the other and constituting acondenser; an inductance coil surrounding the outer of said cylinders; asliding connection between said coil and the inner one of saidcylinders; a sliding connection between said latter cylinder and saidcoil; and a wave indicator connected to both of said cylinders,substantially as described.

3. In a Hertzian wave meter the combination of a pair of concentricmetallic cylinders insulated from each other, the inner of which isprovided with an arm and an extension parallel to its axis; aninductance coil surrounding the outer of said cylinders; a slidingconnection between said extension and one convolution of said coil; asliding connection between said inner cylinder and the other end of saidcoil; and means to indicate the lengths of impinging waves,substantially as described.

, 4. In a Hertzian wave meter the combination of a pair of concentricmetallic cylinders insulated from each other, the inner of which isprovided with an arm and an extension parallel to its axis having ascale, an inductance coil surrounding the outer of said cylinders; asliding connection between said extension and one convolution of saidcoil; a sliding connection between said inner cylinder and the outer endof said coil, consisting of an arm having two parallel portions locatedinside and outside of said cylinders; and means to indicate the lengthsof impinging waves, substantially as described.

5. In a Hertzian wave meter the combination of an inner metal cylinderprovided with an ebonite insulating cover; an outer metal cylinder,also, provided with an ebonite insulating cover; said inner cylinder being capable of freely sliding in said outer cylinder, there being an airspace between the cylinders; a coil of wire constituting an inductancesurrounding said outer cylinder; an extension provided with a scalerigid with and disposed substantially parallel to said inner cylinder; aresilient sliding connection between one convolution of said coil andsaid extension; an arm connected to the other end of said inductance,extending'over the outside of said coil and then bent back upon itselfto extend inside said inductance, and 5 provided with a resilientsliding connection with said inner cylinder; a sliding contactregistering with said scale a wave indicator;

a connection between said sliding contact and said wave indicator; and aconnection be 20 tween said wave indicator and said outer cylinder,substantially as described.

In testimony whereof, I afiin my signature,

in presence of two witnesses.

CLIFFORD D. BABCOCK. Vitnesses Mosns ELY, Josnri-r S. IIUNT.

